December 2025: Delivered targeted RTL-aware enhancements and reliability fixes across GEM5 and XiangShan, focusing on memory subsystem accuracy, timing alignment, and robust bug handling. The work improves simulation fidelity, reduces timing drift, and enhances overall memory operation reliability for subsequent design and performance analysis.

Monthly work summary for 2025-11: Focused on improving cache model fidelity in GEM5 OpenXiangShan by aligning D-cache refill timing with RTL behavior, adding load blocking during tag updates, and instrumenting performance impact metrics. The changes enhance simulation accuracy and provide actionable insights for performance tuning, aligning with business goals of reliable system modeling and faster bug detection.

Month: 2025-05 — Stability and correctness improvements for the O3 CPU model in OpenXiangShan/GEM5. Fixed a ROB deadlock in strictlyOrdered load path by marking instructions as CanCommit on first encounter, preventing stalls and simulation hangs, and ensuring correct execution flow. Commit reference included: 5c6ced965df1ec1c89676f11b4c8d05680f210b7.

March 2025: Strengthened GEM5 memory subsystem in OpenXiangShan with focus on realism and reliability. Delivered enhanced split-store handling (deferred load replay; separate store-queue finish states) and corrected misalignment handling (post-TLB lookup). These changes reduce corner-case bugs, raise simulation fidelity for memory accesses, and smooth the path toward upcoming O3 pipeline work.

February 2025 monthly summary for OpenXiangShan/GEM5 focused on delivering core architectural improvements, stabilizing data path behaviors, and strengthening concurrent memory operations. The month emphasized aligning the data cache with XS RTL, preventing miss replay scenarios, and providing a robust AMO ordering pathway for RISC-V to improve data integrity in concurrent workloads.

January 2025 monthly performance summary for OpenXiangShan/GEM5. Focused memory-subsystem work delivering measurable improvements in modularity, configurability, and timing accuracy. Key updates include: (1) LSQ refactor and parameterization to improve code modularity and maintainable timing models, (2) a Load Custom Hint Wakeup mechanism enabling early data forwarding and robust bus-clear handling, and (3) a corrected cache write latency calculation to better reflect block readiness and write delays. These changes support faster experimentation on CPU-O3 timing paths and more reliable performance modeling.

December 2024: OpenXiangShan/GEM5 delivered substantial improvements across the CPU memory subsystem, concurrency correctness, and testing fidelity. Key bug fixes reduced stalls and improved security/monitoring; feature work advanced memory ordering guarantees, prefetcher efficiency, and realistic memory modeling. These changes collectively improve runtime throughput, correctness under concurrent workloads, and visibility into performance characteristics for capacity planning.

November 2024 – OpenXiangShan/GEM5: Delivered core memory subsystem improvements and prefetching coordination to boost memory accuracy, reduce L3 offloads, and enhance O3 throughput. Focused on feature delivery and architectural refinements with clear business value.

OpenXiangShan/GEM5 monthly summary for 2024-10. Deliveries focused on memory subsystem improvements and prefetching enhancements that improve performance and observability.

September 2024 (OpenXiangShan/XiangShan) monthly summary focusing on key achievements and business impact. Delivered a Banked Data Read Timing Optimization to improve memory access efficiency and pipeline determinism in the XiangShan project. The change refactors banked data read logic to separate the kill signal from the valid signal, reducing bank conflicts and timing variance in reads. Key commit documented for traceability.